Buck converters are commonly utilized to convert a high DC voltage to a low DC voltage. A buck converter typically includes a high-side switch disposed between an input and an output of the buck converter, and a low-side switch disposed between the output of the buck converter and ground. The buck converter can include a control circuit to control a duty cycle of either or both of the high-side and low-side switches so as to convert a high input voltage to a low output voltage.
Because the high-side switch is often limited by its switching speed, it is difficult for a conventional buck converter to achieve a conversion ratio (i.e., the ratio of input voltage to output voltage) that is much greater than 10. Additionally, as the conventional buck converters generate high electromagnetic interference and high switching noise during operation, filters are often required to reduce electromagnetic interference (EMI) and switching noise, thereby undesirably increasing the size and manufacturing cost of the conventional buck converters.
Thus, there is a need in the art for a high efficiency power converter that can achieve a high conversion ratio at high switching frequency with low switching loss and low switching noise.